This invention relates to an artificial-airway device capable of establishing sealed application to the laryngeal inlet for ventilating the lungs of a patient and having the further feature of providing drainage of gastric fluid without impairing the ventilating effectiveness of the airway.
Artificial airway devices of the character indicated, but without provision for drainage of a gastric discharge, are exemplified by the disclosures of U.S. Pat. No. 4,509,514; U.S. Pat. No. 5,249,571; U.S. Pat. No. 5,282,464; U.S. Pat. No. 5,297,547; U.S. Pat. No. 5,303,697; and by the disclosure of UK patent 2,205,499. Such devices with additional provision for gastric-discharge drainage are exemplified by U.S. Pat. No. 4,995,388 (FIGS. 7 to 10); U.S. Pat. No. 5,241,956; and U.S. Pat. No. 5,355,879.
In general, such devices aim to provide an airway tube of such cross-section as to assure more than ample ventilation of the lungs, and the designs with provision for gastric drainage have been characterized by relatively complex internal connections and cross-section calculated to serve in difficult situations where substantial solids could be present in a gastric discharge. As a result, the provision of a gastric discharge opening at the distal end of the mask and applicable for direct service of the hypopharynx has been bulky and unduly stiff, thus making for difficulty in properly inserting the mask down the patient's throat. Moreover, undue bulk and stiffness are at cross-purposes to the distal flexibility required for tracking the posterior curvature of the patient's throat, in such manner as to reliably avoid traumatic encounter with the epiglottis and other natural structures of the pharynx.
In most cases of aid to be administered inter alia by relatively unskilled personnel of first-aid and rescue squads, the real need is for relatively simple structure which can be quickly installed to establish a sealed airway passage, and at minimum incremental cost or complexity of installation to provide at least an ability to drain a liquid gastric discharge, virtually as soon as the airway passage has been sealed.